Automatic knife sharpener



Sept. 5, 1933. NAGY AUTOMATIC KNIFE SHARPENER Filed .May 31, 1930 4 Sheets-Sheet 1 of INVENTOR.

f ATTORNEY.

| NAGY 1,925,108

AUTOMATIC KNIFE SHARPENER Sgpt. 5, 1933.

Filed May 31, 1930 4 Sheets-Sheet 2 ATTORNEY.

Sept. 5, 1933. NAGY 1,925,108

AUTOMATIC KNIFE SHARPENER Filed May 31, 1930 4 Sheets-Sheet 3 INVENTO R.

ATTORNEY.

f QT lhl 3; 4 W M L J Z M/ CM? Sept. 5, 1933. L. NAGY 1,925,108

AUTOMATIC KNIFE SHARPENER Filed May 31, 1930 4 Sheets-Sheet 4 INVEN TOR.

' Patented Sept. 5, 1933 AUTOMATIC KNIFE smmrma Louis Nagy, Detroit, Mibh assignonof one-half to Stephen FJHalach, Detroit, Mich.

Application May 31, 1930. Serial No. 458,648 1 Claim. (Cl. 51-80) The object of my invention is to produce a device for quickly and accurately sharpening knife blades.

Another object is to produce a mechanical 6 knife blade sharpener that is automatic and that will always re-grind the blades with the same edge angles.

A further object is to produce a mechanical device that will quickly sharpen a knife blade without producing a feather edge thereon.

A still further object is to produce an automatic knife sharpener that is simple in construction, easily and efliciently operated and that can-be manufactured at a very low cost.

These several objects are attained in the preferred form by the construction and arrangement of parts more fully hereinafter set forth.

Similar parts on all drawings are marked by similar numerals and letters.

Fig. 1 is a front side view of the assembled device showing the flnishing-wheels and exterior frame structure.

Fig. 2 is a top view of the assembled device showing the guard means and the knifeblade passage as provided therebetween.

Fig. 3 is the back side view of the sharpener showing the courser cutting wheels mounted therein.

Fig. 4 is a top view of the sharpening device with the top wheel guards removed, showing the relative positions of the operating mechanism.

Fig. 5 is an end view taken on the line 5-5 of the Fig. 1 showing the automatic wheel adjusting means.

Fig. 6 is an end view taken on the line 6-6 of the Fig. 1 showing the operating crank and connecting means for rotating the sharpener mecha-, msm.

Fig. 7 is a vertical sectional view crosswise of the device taken on the line 7-7 of the Fig. 1, showing the adjustable mounting block and the relative positions of the operating shafts.

Fig. 8 is a vertical sectional view cross-wise of the device, taken on the lines 8-8 of Fig. 1 showing the general arrangement of the driving mechanism.

Fig. 9 is a vertical sectional view length-wise of the device taken on the line 99 of Fig. 2 showing the automatic adjusting means for holding the sharpening wheels together and means for driving these wheels in opposite directions.

Fig. 10 is an end view taken on the line 66 of Fig. 1 showing an'alternate form of power means, where the operating crank is replaced by a small electric motor.

, In general, my device comprises a rigid closed casing suitable for mounting on the edge of a table or like supports. Within the casing is rotatably mounted two cutting wheel shafts,

each having different grades of wheels on its opposite ends, and so positioned within the frame that the pairs of wheel edges coincide and form a surface rolling contact with each other.

A power shaft is mounted lengthwise through the frame and provided with operating means for engaging the two wheel shafts and rotating them-fin opposite directions. Automatic adjusting means is provided for retaining a wheel surface oontact at all times.

I will now describe more fully the detailed construction of my device referring to the drawings and the marks thereon.

The casing --1 is made a rectangular box shaped frame, open along the side and top walls, and is preferably made of a rectangular shaped 7 metal base block a having thin rectangular end plates band cfixedly attached thereto by the screws --2, said end plates being of suflicient size to completely cover the base block and extend thereabove. The base 0 block -ais formed with three parallel grooves d-, e and ,falong the top side thereof extending the full length of the block, said grooves having vertical, parallel'side walls. on

the bottom side of the base -a is formed a pro- 5 jecting L-shaped clamp arm g, attached thereto at one edge of the block and extended to nearly a central position therebeneath. A threaded clamp screw 3- is mounted within the outer end of the clamp arm --g, and is provided with a swivel cap hon the inner screw end, the clamp arm and screw being designed to engage. a horizontal table top or shelf support for rigidly and securely clamping the casing 1-- thereto. If desired, the casing --1 may be made of cast metal and formed of a single piece. Withinthe central groove eof the base block are slidably mounted two adjustable bearing blocks --4-- and --5--, capable of movement therein lengthwise of the groove. The bearing blocks -4 and -5 are made of metal, preferably formed a hollow rectangular box shaped casting, open at the top side, and of dimensions to fit and engage the groove side walls and allowing suflicient space between the two blocks for adjustment thereof along the groove, both bearing blocks being pro.- jected above the base block -a-. Throughthe tops of the bearing blocks --4- and-"+5- are mounted short horizontal-wheel shafts --6- and =--7-, both rotatably mounted therein by'short tubular bearings -8 pressed within wall sockets and fixedly attached therein by hollow set screws 9- mounted within the bearing block sidewalls. The wheel shafts -6 and --'I-- are positioned cross-wise of the casing --1--, at right angles to the base groove e--, and are opposite and parallel to each other, said shafts being extended outside the bearing block walls at each side thereof, and carry mounted thereon pairs of grinding wheels -10 and 1 1- securely attached thereto by the shaft collars 12- and 13 and the threaded lock nuts 14 and 14ain the ordinary manner, said lock nuts 14- and -14abeing made with right and left hand threads for the respective shaft ends as required for securely retaining the grinding wheels thereon by rotation thereof against the threaded nuts. The pairs of grinding wheels are positioned to project into the side base grooves --dr and f-, and the wheels of each pair are placed directly opposite each other and forming a rim surface contact at all times, both pairs of wheels rolling together and always in opposite directions, the top of all wheels turning outward and away from each other as indicated by the arrows on Figs. 1 and 3 of the drawings. It is preferred that the wheels 10- be made of courser materials for cutting steel while the wheels 11 be made of finer materials for producing a fine finishing surface when grinding the edges of steel blades. The exact materials of the grinding wheels of both --l0- and -11 may be varied, and suchv grades of grinding wheels used as may best suit the purpose and the type of knife to be sharpened thereon. Fixedly mounting on the wheel shafts 6--- and -'7-, inside the hollow bearing blocks 4- and -5 and between the tubular bearings -8-, are the worm drive gears 15- and --l5a, and which gears are made by right and left hand helical teeth. Directly beneath the wheel shafts 6 and 7- is mounted a cylindrical drive shaft 16-, which is positioned lengthwise of the casing -1- and passes through both bearing blocks 4- and 5- and the casing end plates b and -c-, said shaft being at right angles to the shafts --6-- and 7 and parallel to the centerline of the base groove e. The drive shaft -16 is rotatably mounted through the bearing blocks 4- and -5 by the short tubular bushings -17 pressed within the wall sockets and fixedly attached thereto by the hollow set-screws -18-- mounted in the bearing block side walls. The ends of the shaft --16- are-supported in the casing end bearings 19- and 20 fixedly mounted in the end plates band c-. The shaft 16- is preferably turned with shouldered ends ]c to prevent any endwise movement thereof, although small shaft collars may be used on the shaft ends if desired, and for the same purpose. One end of the shaft 16- is extended beyond the casing end plate --band carries a small pinion gear --2 1- fixedly mounted thereon. The, pinion gear 21-- meshes with a large drive gear 22 pivotally attached to the outer face of the casing end b, said gear 22-- being provided with a turning handle 23- fixedly attached thereto, and suit-.

able for applying manual power thereto for causing rotations of the drive shaft -16. Splined to the drive shaft 16-- within the hollow bearing blocks 4 and 5- are worm gears -'--15-- and -15a also formed with right and left hand helical teeth, and which mesh with like corresponding gears mounted on the wheel shafts --6- and '7-'. The gears as mounted on the drive shaft by the attached gears 21- and 22-- will likewise rotate the-connected shafts and attached grinding wheels 10- and -l1-- in opposite directions. Through the bottom section of the bearing blocks 4-- and 5 is mounted an adjusting screw -24-, also positioned lengthwise of the casing and parallel to the drive shaft 16- and casing base groove e, the ends of said adjusting screw being supported by bearings 25- formed in the casing end walls. One end l-- of the adjusting screw is extended through the casing end bearing and carries fixedly mounted thereon an adjusting arm 26. The arm 26 is extended along the casing end wall and carries attached to the outer end thereof a tension coil spring 27- which has its opposite endattached to a fixed wall pin 28' mounted in the casing end, said spring being designed and stressed for causing a turning moment on the adjusting screw 24-- at all times. The screw --24-- is formed with double threaded sections mand nhaving right and left hand threads respectively thereon, each section engaging correspondingly threaded collars --p and -s formed within the bearing blocks --4 and 5-, and thus causing said bearing blocks to be moved in opposite directions along the base groove --e upon any turning of the adjusting screw 24. The arrangement of the right and left hand threads on said screw 24- and the attached tension spring arm 26 being designed to move said bearing blocks 4- and -5 together for retaining a grinding wheel contact at all times and under the spring tension. The hollow bearing block chambers --w are preferably filled with thick grease for lubricating 5 the gears and preventing gear noises when operating at high speed. The hollow set screws 9 and '18- provide means for oiling the shaft bearing on the shafts 6- and 7-- and --16, by an extension oil hole formed through 20 the tubular bushings -8 and 17. Over the top of each grinding wheel is mounted a guard plate 29, designed to inclose the upper portions of the grinding wheels -10 and 11- and also cover the upper open ends of the bearing blocks 4- and 5--. The guards 29- are separated slightly at the center, directly over the grinding wheel contact edges, and are provided with spring guide clips 30- formed along the inner edges thereof, said clips being preferably placed in pairs, opposite each other, and suitable for receiving a knife blade 31 therebetween and guiding same along a vertical plane through the wheel contact edges, and as shown in Figs. 1 and 2 of the drawings. 1'

If desired, the driving gear 22- and hand crank 23- may be replaced by an electric motor 32- as illustrated in Fig. 10 of the drawings, and the size of the pinion gear --2ladjusted accordingly. The operation of the device is the same as heretofore described.

In operating my device for sharpening knife blades, the casing -1- must first be securely attached to a horizontal table top or shelf support, by the clamp screw -3, and it is preferred for the best results that the base grooves -'dand j be partially filled with oil, sufficiently for the grinding wheels to dip therein, and as the pairs of cutting wheels 10- and --11- are rotated in opposite directions, the wheel tops ro- 1150 tating outward, a knife blade -31 may be inserted between the guard clips 30- forcing the knife edge downward to engage the pairs of grinding wheels --10 and 1 1- near the contact points, and then drawing the knife blade lengthwise through between the rotating grinding wheels, preferably in the direction from the courser toward the finer wheel. The process may be repeated until the blade is sharpened and always grinding the blade at exact the same angle and without producing a feather edge thereon.

If desired, and for constructing a. cheaper grinding device, one set of grinding wheels may be removed or omitted altogether. The operation is the same as before.

It is apparent that my device is subject to various modifications in both mechanical details and design-without departing from the spirit of my invention, and I claim as my invention the design as herein shown and any design that is substantially substitution of parts herein shown.

Having fully described my automatic knife sharpener, what I claim as my invention and desire to secure by Letters Patent is: r

A grinding device adapted for sharpening knife blades, comprising a suitable casing frame having clamping means for fixedly attaching same to a support member, two bearing blocks slidably mounted within said casing frame movable only along a plane lengthwise of said casing, a threaded adjusting screw mounted through said casing frame and bearing blocks capable of adjusting the block position therein lengthwise of said casing frame, (a turning lever mounted on said threaded adjusting screw and provided with a tension coil spring attached thereto and also fixedly connected to the casing capable of causing rotation of said threaded adjusting shaft), a driving shaft having' right and left hand worm gears thereon rotatably mounted through the top of said frame and bearing blocks, parallel wheel shafts rotatably mounted through said bearing blocks at right angles to said drive shaft and connected thereto by right and left hand worm gears in a manner capable of causing rotation of said wheel shafts in opposite directionsas the drive shaft is rotated, pairs of oppositely disposed grinding wheels mounted on the ends of the parallel wheel shafts, said oppositely disposed grinding wheels being set with rolling surface contact with each other, a-guard shield mounted over the casing top and carrying knife guides-thereon capable of guiding a knife blade between the said grinding wheels, and power means mounted on said casing connected to the drive shaft for causing continuous rotations of the rotatably mounted grinding wheels.

LOUIS NAGY. 

